1. Field of the Invention
The invention relates to a self-propelled construction machine, in particular cold milling machine, recycler, surface miner, and to a method for milling off and transporting away a milled-off stream of material.
2. Description of the Prior Art
When removing ground or road material using a road milling machine, milled material is produced that is loaded onto a transport vehicle by the road milling machine by means of a conveying device. In this arrangement, the conveying device may comprise one or multiple transport belts which accept the material from the milling drum and unload it at a discharge end along a parabolic discharge trajectory. Loading of the milled material is effected in operation, that is, while the road milling machine and the transport vehicle are in motion. In the process, it is of significance to transfer the milled material onto the transport vehicle in a controlled fashion as the milled-off material is otherwise not unloaded to a specified point of discharge and may impair the traffic flowing alongside or, if the milled material does not entirely come down on the loading surface of the transport vehicle, causes additional sweeping operations.
To guide the stream of material, at least the last section of the conveying device as seen in conveying direction may preferably be mounted to pivot laterally and/or in height, in which case the parabolic trajectory can additionally be influenced by means of the adjustment of the conveying speed.
The properties of the milled-off material differ depending on the task to be performed, for example, fine milling or the removal of complete road pavements, as well as on the operating parameters adjusted, for example, the advance speed of the road milling machine, the milling depth and the type of the milled-off material.
The quantity of the material milled off per unit of time, as well as the composition of the same and the size of the fragments of milled material, in particular, may differ.
It is generally known to load the milled-off material onto a transport vehicle by means of one or multiple successive transport belts.
With steep-incline conveyors, it is also known to use a double-belt belt conveyor (EP 0 249 084).
With the simple transport belts known from road milling machines, a discontinuous stream of material may form as a result of the inhomogeneity of the milled material and the changing quantity of the milled material.
This is due to the fact that, depending on the size of the fragments of the milled-off material, a relative movement of the fragments among themselves and to the transport belt may result, namely, in particular if there is very much or very little milled-off material on the transport belt, or in the case of slab-like fragments of the milled-off material.
A fluctuating amount of slip may form between the milled-off material and the transport belt, namely, in particular in the case of a high speed of the transport belt. As a consequence, different discharge speeds of individual components of the milled-off material may occur, in which case, in addition, flight paths of the different fragments of the milled-off material deviating from the specified parabolic trajectory may result. A further consequence is that, in the mean, the effective discharge speed is lower than the speed of the transport belt which results in a loss of energy.
In addition, a decelerated stream of material is more vulnerable to exterior influences, such as wind loads acting transverse to the transport belt, as the kinematic energy is reduced in conveying direction.